[Go] สรุปวิธีที่ Go ใช้ implements type http.ResponseController ใน Go 1.20

type ResponseController struct {
	rw ResponseWriter
}

func NewResponseController(rw ResponseWriter) *ResponseController {
	return &ResponseController{rw}
}

func (c *ResponseController) Flush() error

func (c *ResponseController) Hijack() (net.Conn, *bufio.ReadWriter, error)

func (c *ResponseController) SetReadDeadline(deadline time.Time) error

func (c *ResponseController) SetWriteDeadline(deadline time.Time) error

// Flush flushes buffered data to the client.
func (c *ResponseController) Flush() error {
	rw := c.rw
	for {
		switch t := rw.(type) { // ใช้ switch type assertion
		case interface{ FlushError() error }: // ใช้ interface literal เลยไม่สร้าง type ใหม่
			return t.FlushError()
		case Flusher: // เช็คจาก interface http.Flusher
			t.Flush()
			return nil
		case rwUnwrapper:
			rw = t.Unwrap()
		default:
			return errNotSupported()
		}
	}
}

// Hijack lets the caller take over the connection.
// See the Hijacker interface for details.
func (c *ResponseController) Hijack() (net.Conn, *bufio.ReadWriter, error) {
	rw := c.rw
	for {
		switch t := rw.(type) {
		case Hijacker:
			return t.Hijack()
		case rwUnwrapper:
			rw = t.Unwrap()
		default:
			return nil, nil, errNotSupported()
		}
	}
}

// SetReadDeadline sets the deadline for reading the entire request, including the body.
// Reads from the request body after the deadline has been exceeded will return an error.
// A zero value means no deadline.
//
// Setting the read deadline after it has been exceeded will not extend it.
func (c *ResponseController) SetReadDeadline(deadline time.Time) error {
	rw := c.rw
	for {
		switch t := rw.(type) {
		case interface{ SetReadDeadline(time.Time) error }:
			return t.SetReadDeadline(deadline)
		case rwUnwrapper:
			rw = t.Unwrap()
		default:
			return errNotSupported()
		}
	}
}

// SetWriteDeadline sets the deadline for writing the response.
// Writes to the response body after the deadline has been exceeded will not block,
// but may succeed if the data has been buffered.
// A zero value means no deadline.
//
// Setting the write deadline after it has been exceeded will not extend it.
func (c *ResponseController) SetWriteDeadline(deadline time.Time) error {
	rw := c.rw
	for {
		switch t := rw.(type) {
		case interface{ SetWriteDeadline(time.Time) error }:
			return t.SetWriteDeadline(deadline)
		case rwUnwrapper:
			rw = t.Unwrap()
		default:
			return errNotSupported()
		}
	}
}

// errNotSupported returns an error that Is ErrNotSupported,
// but is not == to it.
func errNotSupported() error {
	retu